Distal protection device and method

ABSTRACT

An emboli capturing system captures emboli in a body lumen. A first elongate member has a proximal end and a distal end. An expandable emboli capturing device is mounted proximate the distal end of the first elongate member, and is movable between a radially expanded position and a radially contracted position. When in the expanded position, the emboli capturing device forms a basket with a proximally opening mouth. A second elongate member has a proximal and a distal end with a lumen extending therebetween. The lumen is sized to slidably receive a portion of the first elongate member. An expandable delivery device is mounted to the distal end of the second elongate member and is movable from a radially retracted position to a radially expanded position. The delivery device has a receiving end configured to receive the emboli capturing device, and retains at least the mouth of the emboli capturing device in a radially retracted position.

INCORPORATION BY REFERENCE

This is a continuation of application Ser. No. 10/160,450 filed May30,2002 now U.S. Pat. No. 6,663,652, which in turn is a continuation ofapplication Ser. No. 09/735,332 filed on Dec. 12, 2000, which in turn isa continuation of application Ser. No. 09/409,497 filed on Sep. 30, 1999now U.S. Pat. No. 6,245,089, which in turn is a continuation ofapplication Ser. No. 08/943,358 filed on Oct. 3, 1997, now U.S. Pat. No.6,001,118, which in turn is a continuation-in-part of application Ser.No. 08/810,825 filed on Mar. 6, 1997, now U.S. Pat. No. 5,814,064, whichin turn is a continuation-in-part of application Ser. No. 08/813,794filed on Mar. 6, 1997, now U.S. Pat. No. 5,827,324.

The following co-pending patent application is hereby incorporated byreference U.S. patent application Ser. No. 08/813,794, entitled DISTALPROTECTION DEVICE which was filed on Mar. 6, 1997, and assigned to thesame assignee as the present application.

BACKGROUND OF THE INVENTION

The present invention deals with an emboli capturing system. Morespecifically, the present invention deals with an emboli capturingsystem and method for capturing embolic material in a blood vesselduring an atherectomy or thrombectomy procedure.

Blood vessels can become occluded (blocked) or stenotic (narrowed) inone of a number of ways. For instance, a stenosis may be formed by anatheroma which is typically a harder calcified substance which forms onthe lumen walls of the blood vessel. Also, the stenosis can be formed ofa thrombus material which is typically much softer than an atheroma, butcan nonetheless cause restricted blood flow in the lumen of the bloodvessel. Thrombus formation can be particularly problematic in asaphenous vein graft (SVG).

Two different procedures have developed to treat a stenotic lesion(stenosis) in vasculature. The first is to deform the stenosis to reducethe restriction within the lumen of the blood vessel. This type ofdeformation (or dilatation) is typically performed using balloonangioplasty.

Another method of treating stenotic vasculature is to attempt tocompletely remove either the entire stenosis, or enough of the stenosisto relieve the restriction in the blood vessel. Removal of the stenoticlesion has been done through the use of radio frequency (RF) signalstransmitted via conductors, and through the use of lasers, both of whichtreatments are meant to ablate (i.e., super heat and vaporize) thestenosis. Removal of the stenosis has also, been accomplished usingthrombectomy or atherectomy. During thrombectomy and atherectomy, thestenosis is mechanically cut or abraded away from the vessel.

Certain problems are encountered during thrombectomy and atherectomy.The stenotic debris which is separated from the stenosis is free to flowwithin the lumen of the vessel. If the debris flows distally it canocclude distal vasculature and cause significant problems. If it flowsproximally, it can enter the cirulatory system and form a clot in theneural vasculature, or in the lungs, both of which are highlyundesirable.

Prior attempts to deal with the debris or fragments have includedcutting the debris into such small pieces (having a size on the order ofa blood cell), that they will not occlude vessels within thevasculature. However, this technique has certain, problems. Forinstance, it is difficult to control the size of the fragments of thestenotic lesion which are severed. Therefore larger fragments can besevered accidentally. Also, since thrombus is much softer than anatheroma, it tends to a break up easier when mechanically engaged by acutting instrument. Therefore, at the moment that the thrombus ismechanically engaged, there is a danger that it can be dislodged inlarge fragments which would occlude the vasculature.

Another attempt to deal with debris severed from a stenosis is to removethe debris, as it is severed, using suction. However, it may benecessary to pull quite a high vacuum in order to remove all of thepieces severed from the stenosis. If a high enough vacuum is not used,all of the severed pieces will not be removed. Further, when a highvacuum is used, this can tend to cause the vasculature to collapse.

A final technique for dealing with the fragments of the stenosis whichare severed during atherectomy is to place a device distal to thestenosis during atherectomy to catch the pieces of the stenosis as theyare severed, and to remove those pieces along with the capturing devicewhen the atherectomy procedure is complete. Such capture devices haveincluded expandable filters which are placed distal of the stenosis tocapture stenosis fragments. Problems are also associated with thistechnique. For example, delivery of such devices in a low profile,pre-deployment configuration can be difficult. Further, some devicesinclude complex and cumbersome actuation mechanisms. Also, retrievingsuch capture devices, after they have captured emboli, can be difficultas well.

SUMMARY OF THE INVENTION

An emboli capturing system captures emboli in a body lumen. A firstelongate member has a proximal end and a distal end. An expandableemboli capturing device is mounted proximate the distal end of the firstelongate member, and is movable between a radially expanded position anda radially contracted position. When in the expanded position, theemboli capturing device forms a basket with a proximally opening mouth.A second elongate member has a proximal and a distal end with a lumenextending therebetween. The lumen is sized to slidably receive a portionof the first elongate member. An expandable delivery device is mountedto the distal end of the second elongate member and is movable from aradially retracted position to a radially expanded position. Thedelivery device has a receiving end configured to receive the embolicapturing device, and retains at least the mouth of the emboli capturingdevice in a radially retracted position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a distal protection device of the present invention in adeployed position.

FIG. 2 shows the distal protection device shown in FIG. 1 in a collapsedposition.

FIG. 3 shows an end view of a portion of the distal protection deviceshown in FIGS. 1 and 2.

FIG. 4 shows a cross-sectional view of a portion of the distalprotection device shown in FIGS. 1-3 in the deployed position.

FIG. 5 shows a second embodiment of the distal protection deviceaccording to the present invention in a deployed position.

FIG. 6 shows an end view of the distal protection device shown in FIG.5.

FIG. 7 shows a cross-sectional view of the distal protectiondevice-shown in FIGS. 5 and 6 in the collapsed position.

FIG. 8 shows a third embodiment of a distal protection device accordingto the present invention in a deployed position.

FIG. 9 is a side sectional view of an alternate embodiment illustratinghow the expandable members of the present invention are attached to aguidewire.

FIG. 10 is a sectional view taken along section lines 10—10 in FIG. 9.

FIGS. 11A and 11B show a fourth and fifth embodiment, respectively, of adistal protection device according to the present invention in adeployed position.

FIG. 12 illustrates the operation of a distal protection device inaccordance with the present invention.

FIGS. 13A-17B show additional embodiments of distal protection deviceswhich expand and collapse based on movement of a mechanical actuator.

FIGS. 18A-18D illustrate an additional embodiment of a distal protectiondevice which is deployed and collapsed using a rolling flapconfiguration.

FIG. 19 illustrates another embodiment in accordance, with the presentinvention in which the protection device is deployed using fluidpressure and a movable collar.

FIGS. 20A and 20B illustrate another aspect of the present invention inwhich two longitudinally movable members used to deploy the distalprotection device are disconnectably locked to one another.

FIGS. 21A-21C illustrate another embodiment in accordance with thepresent invention in which the protection device is formed with a shapememory alloy frame and an attached filter or mesh mounted to the frame.

FIGS. 22A-22C illustrate another embodiment in accordance with thepresent invention in which the distal protection devices shown in FIGS.21A-21C are delivered and deployed.

FIGS. 23A-23E illustrate another embodiment in accordance with thepresent invention in which the distal protection devices shown in FIGS.21A-21C are retrieved.

FIGS. 24A-24C illustrate another embodiment in accordance with thepresent invention in which the distal protection devices shown in FIGS.21A-21C are retrieved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates protection device 10 in a deployed position withinthe lumen of a blood vessel 12. Protection device 10 preferably includeshollow guidewire 14 (or a hypotube having the same general dimensions asa guidewire) having a coil tip 16, and a capturing assembly 18.Capturing assembly 18, in the embodiment shown in FIG. 1, includes aninflatable and expandable member 20 and mesh 22.

An interior of expandable member 20 is preferably coupled for fluidcommunication with an inner lumen of guidewire 14 at a distal region ofguidewire 14. When deployed, inflatable member 20 inflates and expandsto he position shown in FIG. 1 such, that capturing assembly 18 has anouter periphery which approximates the inner periphery of lumen 12.

Mesh 22 is preferably formed of woven or braided fibers or wires, or amicroporous membrane, or other suitable filtering or netting-typematerial. In membrane having holes therein with a diameter ofapproximately 100 μm. Mesh 22 can be disposed relative to inflatablemember 20 in a number of different ways. For example, mesh 22 can beformed of a single generally cone-shaped piece which is secured to theouter or inner periphery of inflatable member 20. Alternatively, mesh 22can be formed as a spiral strip which is secured about the outer orinner periphery of inflatable member 20 filling the gaps between theloops of inflatable member 20. Alternatively, mesh 22 can be formed of anumber of discrete pieces which are assembled onto inflatable member 20.

Hollow guidewire 14 preferably has a valve 24 coupled in a proximalportion thereof. During operation, a syringe is preferably connected tothe proximal end of guidewire 14, which preferably includes a fluidhypotube. The syringe is used to pressurize the fluid such that fluid isintroduced through the lumen of hollow, guidewire 14, through valve 24,and into. inflatable member 20. Upon being inflated, inflatable member20 expands radially outwardly from the outer surface of guidewire 14 andcarries mesh 22 into the deployed position shown in FIG. 1. In this way,capturing assembly, or filter assembly, 18 is deployed distally ofstenosis 26 so that stenosis 26 can be, severed and fragmented, and sothe fragments from stenosis 26 are carried by blood flow (indicated byarrow 28) into the basket or chamber formed by the deployed filterassembly 18. Filter assembly 18 is then collapsed and removed fromvessel 12 with the fragments of stenosis 26 contained therein.

FIG. 2 illustrates protection device 10 with filter assembly 18 in thecollapsed position. Similar items to those shown in FIG. 1 are similarlynumbered. FIG. 2 illustrates that mesh 22 is easily collapsible withinflatable member 20. In order to collapse filter assembly 18, fluid ispreferably removed from inflatable member 20 through the lumen of hollowguidewire 14 and through two-way valve 24. This can be done using thesyringe to pull a vacuum, or using any other type of suitable fluidremoval system.

Inflatable member 20 is preferably formed of a material having someshape memory. Thus, when inflatable member 20 is collapsed, it collapsesto approximate the outer diameter of hollow guidewire 14. In onepreferred embodiment, inflatable member 20 is formed of a resilient,shape memory material such that it is inflated by introducing fluidunder pressure through the lumen in hollow guidewire 14 into inflatablemember 20. When pressure is released from the lumen in hollow guidewire14, inflatable member 20 is allowed to force fluid out from the interiorthereof through two-way valve 24 and to resume its initial collapsedposition. Again, this results in filter assembly 18 assuming itscollapsed position illustrated in FIG. 2.

FIG. 3 illustrates a view taken, from the distal end of device 10 withmesh 22 removed for clarity. FIG. 3 shows that, when inflatable member20 is deployed outwardly, mesh 22 (when deployed between the loops ofinflatable member 20) forms a substantially lumen-filling filter whichallows blood to flow therethrough, but which provides a mechanism forreceiving and retaining stenosis fragments carried into mesh 22 by bloodflow through the vessel.

FIG. 3 also shows that inflatable member 20 preferably has a proximalend portion 29 which is connected to the outer periphery of guidewire14. Although end 29 need not be connected to guidewire 14, it ispreferably connected using adhesive or any other suitable connectionmechanism. By fixedly connecting proximal end portion 29 to guidewire14, this increases the stability of the filter assembly 18 upondeployment.

FIG. 4 is a cross-sectional view of a portion of protection device 10.FIG. 4 shows protection device with filter assembly 18 in the expandedor deployed position. FIG. 4 also better illustrates that guidewire 14is hollow and has a longitudinal lumen 30 extending therethrough.Longitudinal lumen 30 is connected in fluid communication with aninterior of inflatable member 20 through aperture 32 which is providerin the wall of guidewire 14. FIG. 4 also shows that, in one preferredembodiment, a core wire 34 extends through lumen 30 from a proximal endthereof where it is preferably brazed to a portion of a hypotube whichmay be connected to the proximal portion of guidewire 14. The core wire34 extends to the distal end of guidewire 14 where it is connected tocoil tip 16. In one preferred embodiment, coil tip 16 is brazed orotherwise welded or suitably connected to the distal portion of corewire 34.

FIG. 4 further shows that, in the preferred embodiment, inflatablemember 20 inflates to a generally helical, conical shape, to form abasket opening toward the proximal end of guidewire 14. FIG. 4 furtherillustrates, in the preferred embodiment, mesh 22 has a distal portion38 which is connected to the exterior surface of guidewire 14, at adistal region thereof, through adhesive 36 or any other suitableconnection mechanism.

FIG. 5 illustrates a second embodiment of a distal protection device 40in accordance with the present invention. Device 40 includes hollowguidewire 42, filter assembly 44 and coil tip 16. Filter assembly 44includes a plurality of inflatable struts 46 and mesh 47. Each strut 46has a distal end 48 and proximal end 50. Inflatable struts 46 also havean interior which is coupled in fluid communication, through distal end48 thereof, with the lumen in hollow guidewire 42. Struts 46 arepreferably configured such that, upon being inflated, the proximal ends50 deploy radially outwardly away from the outer surface of hollowguidewire 42 to assume a dimension which approximates the innerdimension of lumen 58 in which they are inserted.

Mesh 47, as with mesh 22 shown in FIG. 1, is deployed either on theouter or inner surface of inflatable struts 46, such that, when theinflatable struts 46 are deployed radially outwardly, mesh 47 forms agenerally conical basket opening toward the proximal end of hollowguidewire 42. As with the embodiment shown in FIG. 1 mesh 47 can beapplied to either the outer or the inner surface of struts 46. It can beapplied to struts 46 as one unitary conical piece which is adhered aboutdistal ends 48 of struts 46 using adhesive (or about the distal end ofguidewire 42 using adhesive) and secured to the surface of the struts 46also using adhesive. Alternatively, mesh 47 can be applied to struts 46in a plurality of pieces which are individually or simultaneouslysecured to, and extend between, struts 46.

FIG. 6 is an end view of distal protection device 40 shown in FIG 5taken from the distal end of distal protection device 40. When struts 46are deployed outwardly, mesh 47 forms a substantially lumen-fillingfilter which allows blood to flow therethrough, but which provides amechanism for receiving and retaining stenosis fragments from stenosis56 carried into mesh 47 by blood flow through the vessel.

FIG. 7 is a cross-sectional view of a portion of distal Protectiondevice 40 shown in FIGS. 5 and 6. FIG. 7 shows filter assembly 44 in thecollapsed position in which it approximates the outer diameter ofguidewire 42. FIG. 7 also shows that, in the preferred embodiment, thedistal ends 48 of struts 46 are in fluid communication with an innerlumen 52 in hollow guidewire 42 through apertures 54 in the wall ofguidewire 42.

FIG. 8 illustrates another embodiments of a distal protection device 60in accordance with the present invention. Distal protection device 60 issimilar to those shown in other figures, and similar items are similarlynumbered. However, distal protection device 60 includes hollow guidewire63 which has a lumen in fluid communication with an interior of a pairof inflatable struts 62. Inflatable struts 62 have an inner surface 64which is generally concave, or hemispherical, or otherwise appropriatelyshaped such that it extends about a portion of the outer surface ofhollow guidewire 63. Mesh portions 66 extend between the inflatablestruts 62 so that inflatable struts 62 and mesh portions 66, whendeployed outwardly as shown in FIG. 8, form a basket shape which openstoward the proximal end of hollow guidewire 63.

FIG. 9 illustrates another system for attaching inflatable struts to ahollow guidewire for a distal protection device 70 in accordance withthe present invention. Distal protection device 70 is similar to thedistal protection devices shown in the previous figures in that a,plurality of inflatable struts 72 are provided and preferably have amesh portion extending therebetween. For the sake of clarity, the meshportion is eliminated from FIG. 9. However, it will be understood that,when deployed, distal protection device 70 forms a generallybasket-shaped filter assembly which opens toward the proximal end ofhollow guidewire 74.

In the embodiment shown in FIG. 9, hollow guidewire 74 has a distal end75 which is open. An endcap 76 is disposed about the distal end 75 ofhollow guidewire 74 and defines an internal chamber or passageway 78.Endcap 76 has a proximal end 80 which has openings therein for receivingthe ends of inflatable struts 72. Thus, in order to inflate inflatablestruts 72, the operator pressurizes fluid within the lumen of hollowguidewire 74 forcing fluid out through distal end 75 of hollow guidewire74, through passageway 78, and into inflatable struts 72. In order tocollapse distal protection device 70, the operator draws a vacuum whichpulls the fluid back out of inflatable struts 72, through passageway 78and, if necessary, into the lumen of hollow guidewire 74.

FIG. 10 is an end view of endcap 76 taken along lines 10—10 in FIG. 9.FIG. 10 shows that proximal end 80 of endcap 76 preferably includes afirst generally central aperture 82 for receiving the distal end ofhollow guidewire 74. Aperture 82 is sized just larger than, orapproximating, the outer diameter of hollow guidewire 74 such that itfits snugly over the distal end 75 of hollow guidewire 74. Endcap 76 isthen fixedly connected to the distal end 75 of hollow guidewire 74through a friction fit, a suitable adhesive, welding, brazing, oranother suitable connection technique.

FIG. 10 also shows that proximal end 80 of endcap 76 includes aplurality of apertures 84 which are spaced from one another about end80. Apertures 84 are sized to receive open ends of inflatable struts 72.In the preferred embodiment, inflatable struts 72 are secured withinapertures 84 using a suitable adhesive, or another suitable connectiontechnique. Also, in the preferred embodiment, spring tip 16 is embeddedin, or otherwise suitably connected to, endcap 76.

FIGS. 11A and 11B show two other preferred embodiments of a distalprotection device in accordance with the present invention. FIG. 11Ashows distal protection device 90 which includes hollow guidewire 92having a lumen running therethrough, inflatable member 94 and meshportion 96. FIG. 11A shows that inflatable member 94, when inflated,forms a ring about the outer surface of hollow guidewire 92. The ringhas an inner periphery 98 which is spaced from the outer surface ofhollow guidewire 92 substantially about the entire radial periphery ofhollow guidewire 92. Mesh portion 96 extends between the outer surfaceof hollow guide 92 and the inner periphery 98 of inflatable member 94.Thus, a substantially disc-shaped filter assembly is provided upondeployment of distal protection device 90. As with the otherembodiments, deployment of distal protection device 90 is accomplishedby providing fluid through the inner lumen of hollow guidewire 92 intoan interior of inflatable member 94 which is in fluid communication withthe inner lumen of hollow guidewire 92.

In one preferred embodiment, end 100 of inflatable, member 94 is coupledto a coupling portion 102 of inflatable member 94 such that stability isadded to inflatable member 94, when it is inflated.

FIG. 11B illustrates another distal protection device 104 which includesa hollow guidewire 106 and an inflatable member 108. Device 104 issimilar to distal protection device 90 except that, rather than havingonly a single inflatable ring upon deployment of distal protectiondevice 104, a plurality of generally equal-diameter rings are formedinto a helix shape. In the preferred embodiment, distal protectiondevice 104 includes a mesh sleeve 110 which extends about the outer orinner surface of the helix formed by inflatable member 108. In oneembodiment, mesh sleeve 110 is connected to the outer surface of hollowguidewire 106 in a region 112 proximate, but distal of, inflatablemember 108. In another preferred embodiment, the proximal end of meshsleeve 110 is connected to the outer perimeter of inflatable member 108.Thus, distal protection device 104 forms a generally basket-shapedfilter assembly which opens toward a proximal end of guidewire 106.

As with the other embodiments, both distal protection device 90 shown inFIG. 11A and distal protection device 104 shown in FIG. 11B arepreferably collapsible. Therefore, when collapsed, the distal protectiondevices 90 and 104 preferably have an outer dimension which approximatesthe outer dimensions of hollow guidewires 92 and 106, respectively.Further, as with the other embodiments, distal protection devices 90 and104 can either be biased in the deployed or collapsed positions, anddeployment and collapse tan be obtained either by pulling a vacuum, orpressurizing the fluid with the lumen of the hollow guidewires 92 and106.

FIG. 12 illustrates the use of a distal protection device in accordancewith the present invention. For the sake of clarity, the presentdescription proceeds with respect to distal protection device 10 only.Device 10 is shown filtering stenosis fragments from the blood flowingthrough the lumen of vessel 12. FIG. 12 also shows a dilatation device120 which can be any suitable dilatation device for dilating, cutting,fragmenting, or abrading, portions of stenosis 26. In the preferredembodiment, device 120 is used in an over-the-wire fashion over hollowguidewire 14. Thus, filter assembly 18 is first advanced (usingguidewire 14) distal of stenosis 26. Then, filter assembly 18 isdeployed outwardly to the expanded position. Dilatation device 120 isthen advanced over guidewire 14 to stenosis 26 and is used to fragmentor abrade stenosis 26. The fragments are received within the basket offilter assembly 18. Filter assembly 18 is then collapsed, and filterassembly 18 and dilatation device 120 are removed from vessel 12.Alternatively, dilatation device 120 can be removed first and filterassembly 18 is then removed along with guidewire 14.

It should be noted that the stenosis removal device (or atherectomycatheter) 120 used to fragment stenosis 26 can be advanced overguidewire 14. Therefore, the device according to the present inventionis dual functioning in that, it captures emboli and serves as aguidewire. The present invention does not require adding an additionaldevice to the procedure. Instead, the present invention simply replacesa conventional guidewire with a multi-functional device.

FIGS. 13A-17B illustrate embodiments of various distal protectiondevices wherein deployments and contraction of the distal protectiondevice is accomplished through a mechanical push/pull arrangement.

FIGS. 13A and 13B illustrate a distal protection device 122. FIG. 13Ashows device 122 in an undeployed position and. FIG. 13B shows device122 in a deployed position. Distal protection device 122 includes aslotted Nitinol tube 124 which has a lumen 126 extending therethrough.Tube 124 has a plurality of slots 128 at a distal region thereof. Thedistal portion of slots 128 are covered by mesh 130 which, in thepreferred embodiment, is a flexible microporous membrane. Device 122also preferably includes a mandrel 132 which extends through the innerlumen 126 of tube 124 and is Attached to the distal end of tube 124. Inthe preferred embodiment, mandrel 132 is attached to the distal end oftube 124 by an appropriate adhesive, brazing welding, or anothersuitable connection technique. Tube 124 also has, on its inner peripheryin a proximal region thereof, a plurality of locking protrusions 134.Lock protrusions 134 are preferably arranged about a proximal expandableregion 136 disposed on mandrel 132.

In order to deploy device 122 into the deployed position shown in FIG.13B, the operator preferably first advances tube 124 distally of thelesion to be fragmented. In the preferred embodiment tube 124 has a sizeon the order of a guidewire, such as, a 0.014 inch outer diameter.Therefore, it easily advances beyond the stenosis to be fragmented Theoperator then pushes on the proximal region of tube 124 and pulls on theproximal end of mandrel 132. This causes two things to happen. First,this causes the struts formed by slots 128 to expand radially outwardlyand carry with them, microporous membrane 130. Thus microporous membrane130 forms a generally basket-shaped filter assembly which opens towardthe proximal end of tube 124. In addition, proximal expandable member136 expand and engages protrusions 134. This locks device 122 in thedeployed and expanded position. In order to move the device 122 to thecollapsed position, the physician simply pushes on mandrel 132 and pullson the proximal end of tube 124. This causes device 122 to return to theundeployed position shown in FIG. 13A.

It should be noted that device 122 can optionally be provided with astainless steel proximal hypotube attachment. Also, the struts definedby slots 128 can be expanded and retracted using a fluid couplinginstead of a mandrel. In other words, the proximal end of tube 124 canbe coupled to a pressurizable fluid source. By making slots 128 verythin, and pressurizing the fluid, the struts expand outwardly. Further,by pulling vacuum on the pressurizable fluid, the struts collapse.

FIG. 14A illustrates distal protection device 140 which is similar tothat shown in FIGS. 13A and 13B, except that the struts 142 are formedof a metal or polymer material and are completely covered by mesh 144.Mesh 144 includes two mesh portions, 146 and 148. Mesh portion 146 isproximal of mesh portion 148 on device 140 and is a relatively loosemesh which will allow stenosis fragments to pass therethrough. Bycontrast, mesh 148 is a fairly tight mesh, or a microporous membrane,(or simply loose mesh portion 146 with a microporous membrane or othersuitable filter material bonded or cast or otherwise disposed thereover)which does not allows the fragments to pass therethrough and thereforecaptures and retains the fragments therein. The mesh portions canprovide a memory set which, in the relaxed position, is either deployedor collapsed.

FIG. 14B illustrates a device 150 which is similar to device 140 shownin FIG. 14A, except struts 142 are eliminated and the two mesh portions146′ and 148′ are simply joined together at a region 152. Also, the twomesh portions 146′ and 148′ are not two, different discrete meshportions but are formed of the same braided mesh material wherein thebraid simply has a different pitch. The wider pitch in region 146′provides a looser mesh, whereas the narrower pitch in region 148′provides a tighter mesh that traps the embolic material.

FIG. 14C illustrates a distal protect on device 160 which is similar tothat shown in FIG. 14A. However, rather than simply providing a slottedtube, distal protection device 160 includes a plurality of struts 162 ona proximal region thereof and a plurality of struts 164 on the distalregion thereof. Struts 162 are spaced further apart than struts 164about the periphery of protection device 160. Therefore, struts 162define openings 166 which are larger than the openings 168 defined bystruts 164 and allow stenosis fragments to pass therethrough. Also,struts 164 have secured to the interior surface thereof a filter or meshportion 170. When deployed, filter portion 170 forms a substantiallybasket-shaped filter device opening toward the proximal region of tube172.

FIG. 15 illustrates the operation of another distal protection device176. Distal protection device 176 includes a tube 178 and a push/pullwire 180. Tube 178 has, at the distal end thereof, a filter assembly182. Filter assembly 182 includes a plurality of preferably metal struts184 which have a microporous membrane, or other suitable mesh 186disposed thereon. Tube 178 also preferably includes end cap 188 andumbrella-like expansion structures 190 disposed at a distal regionthereof. Expansion structure 190 is connected to the distal region oftube 178 and to metal struts 184 such that, when push/pull wire 180 ispulled relative to tube 178, expansion member 190 exerts a radial,outwardly directed force on strut 184 causing them to expand radiallyoutwardly relative to the outer surface of tube 178. This causesmicroporous membrane or mesh 186 to be deployed in a manner openingtoward the proximal end of tube 178 to catch embolic material. Struts184 can also be formed of an appropriate polymer material.

FIGS. 16A and 16B illustrate a protection device in accordance withanother, embodiment of the present invention. FIG. 16A, illustratesdistal protection device 192. Device 192 includes guidewire 194,actuator wire 196, and filter assembly 198. Filter assembly 198 includesan expandable ring 200, such as an expandable polymer or metal or otherelastic material, which has attached thereto mesh 202. Mesh 202 is alsoattached to guidewire 194 distally of ring 200. Actuator wire 196 isattached to sleeve or sheath 204 which is positioned to fit about theouter periphery of expandable ring 200, when expandable ring 200 is inthe collapsed position.

Thus, when sheath 204 is moved distally of expandable ring 200,expandable ring 200, has shape memory which causes it to expand into theposition shown in FIG. 16A. Alternatively, when sheath 204 is pulledproximally by pulling actuator wire 196 relative to guidewire 194,sheath 204 collapses ring 200 and holds ring 200 in the collapsedposition within sheath 204. Manipulating wires 194 and 196 relative toone another causes device 192 to move from the deployed position to thecollapsed position, and vice versa.

FIG. 16B is similar to device 192 except that, instead of having anexpandable ring 200 connected at one point to wire 194, distalprotection device 206 includes expandable member 208 which is formed ofan elastic coil section of wire 194. Thus, elastic coil section 208 hasa shape memory which causes it to expand into the generally helical,conical shape shown in FIG. 16B. However, when sheath 204 is pulledproximally relative to expandable member 208, this causes sheath 204 tocapture and retain expandable member 208 in a collapsed position. Whensheath 204 is again moved distally of expandable member 208, expandablemember 208 returns to its expanded position shown in FIG. 16B carryingwith it mesh 210 into a deployed position. In the preferred embodiment,sheath 204 is formed of a suitable polymer material and expandablemember 208 and expandable ring 200 are preferably formed of Nitinol.

FIGS. 17A and 17B illustrate the operation of another distal protectiondevice 212. Protection device 212 includes guidewire 214 and filterassembly 216. In the preferred embodiment, filter assembly 216 includesa wire braid portion 218 which extends from a distal region of guidewire214 proximally thereof. Braid portion 218 is formed of braided,filaments or fibers which have a shape memory causing them to form adeployed, basket-shaped filter, such as that shown in FIG. 17A, in theunbiased position. Braided portion 218 terminates at its proximal end ina plurality of eyelets 220. One or more cinch wires 222 are preferablythreaded through eyelets 220. By pushing on guidewire 214 and pulling oncinch wires 222, the operator is able to cinch closed, and pullproximally, the proximal portion of mesh 218. This causes mesh 218 tocollapse tightly about the outer surface of wire 214.

Therefore, during operation, the operator holds mesh 218 in thecollapsed position and inserts protection device 212 distally of thedesired stenosis. The operator then allows cinch wire 222 to movedistally relative to guidewire 214. This allows mesh 218 to open to thedeployed position shown in FIG. 17A which has an outer diameter thatapproximates the inner diameter of the lumen within which it isdisposed. Filter assembly 216 is then disposed to capture embolicmaterial from blood flowing therethrough. Once the embolic material iscaptured, the operator again moves cinch wire 222 proximally relative toguidewire 214 to collapse filter assembly 216 and capture and retain theembolic material in filter assembly 216. The device 212 is then removed.

FIG. 17B shows distal protection device 212 except that in theembodiment shown in FIG. 17B, protection device 212 is not disposeddistally of the stenosis, but rather proximally. This results, forexample, in an application where the blood flow is. proximal of thestenosis rather than distal. Further, in the embodiment shown in FIG.17B, guidewire 214 is preferably hollow and the cinch wire 222 extendsthrough the lumen therein. By pushing on guidewire 214, a force isexerted on mesh 218 in the distal direction. This causes, cinch wire 222to tightly close the distal opening in filter assembly 216 and tocollapse mesh portion 218. By contrast, by allowing cinch wire 222 tomove distal relative to hollow guidewire 214, mesh portion 218 expandsand filter assembly 216 is deployed as shown in FIG. 17B.

FIGS. 18A and 18B illustrate a distal protection device 250 inaccordance with another aspect for the present invention. Device 250includes inner embodiment, inner wire 252 is a core wire and outer tube254 has a lumen 256 therein large enough to accommodate longitudinalmovement of inner wire 252 therein. Also, in the preferred embodiment,inner wire 252 has, coupled to its distal end 258, a spring tip 260.

Device 250 includes expandable mesh or braid portion 262. Expandableportion 262 has a proximal end 264 which is attached to the distal end266 of tube 254.

Also, expandable member 262 has a distal end 268 which is attached tothe distal end 258 of inner wire 252.

Expandable member 262 is preferably a mesh or braided material which iscoated with polyurethane. In one preferred embodiment, a distal portionof expandable member 262 has a tighter mesh than A proximal portionthereof, or has a microporous membrane or other suitable filteringmechanism disposed thereover. In another preferred embodiment,expandable member 262 is simply formed of a tighter mesh or braidedmaterial which, itself, forms the filter. FIG. 18A illustrates device250 in a collapsed, or insertion position wherein the outer diameter ofmesh portion 262 closely approximates the outer diameters of eitherinner wire 252 or outer tube 254.

FIG. 18B illustrates device 250 in the deployed position in whichexpandable member 262 is, radially expanded relative to the collapsedposition shown in FIG. 18A. In order to deploy device 250, the outertube 254 is moved distally with respect to inner wire 252 such that thedistal ends 266 and 258 of wires 254 and 252 move longitudinally, towardone another Relative movement of ends 266 and 258 toward one anothercauses the mesh of expandable member 262 to buckle and fold radiallyoutwardly. Thus, the outer diameter of expandable member 262 in thedeployed position shown in, FIG. 18B closely approximates the innerdiameter of a vessel within which it is deployed.

FIG. 18C illustrates device 250 in a partially collapsed position. InFIG. 18C, the distal end 266 of outer tube 254 and the distal end 258 ofinner wire 252 are moved even closer together than they are as shown inFIG. 18B. This causes expandable mesh portion 262 to fold over itselfand form a rolling, proximally directed flap 270. As longitudinalmovement of inner wire 252 proximally with respect to outer tube 254continues, mesh portion 262 continues to fold over itself such that therolling flap portion 270 has an outer radial diameter which continues todecrease. In other words, expandable mesh portion 262 continues to foldover itself and to collapse over the outer periphery of outer tube 254.

FIG. 18D illustrates device 250 in a fully collapsed position in whichit retains emboli captured therein. In FIG. 18D, the distal end 266 ofouter tube 254 has been advanced as far distally as it can relative tothe distal end 258 of inner wire 252. This causes expandable meshportion 262 to fold all the way over on itself such that it lies,against, and closely approximates the outer diameter of, outer tube 254.Device 250 thus captures any emboli filtered from the vessel withinwhich it was deployed, and can be removed while retaining that embolicmaterial.

FIG. 19 illustrates device 280 which depicts a further aspect inaccordance with the present invention. Device 280 includes outer tubed282, core wire 284, transition tube 286, movable plunger 288, expandablemember 290, fixed collar 292 and bias member 294.

In the preferred embodiment, tube 282 comprises a proximal hypotubewhich is coupled, to a plunger that selectively provides fluid underpressure through an inflation lumen 296. Inner wire 284 is preferably atapered core wire which terminates at its distal end in a spring coiltip 298 and which is coupled at its proximal end 300 to transition tube286 Transition tube 286 is preferably an outer polymer sleeve eitherover hypotube 282, or simply disposed by itself and coupled to ahypotube 282. Transition tube 286 is capable of withstanding theinflation pressure provided by the fluid delivered through the inflationlumen 296.

Movable collar 288 is preferably slidably engageable with the interiorsurface of transition tube 286 and with the exterior surface of corewire 284, and is longitudinally movable relative thereto. Slidablecollar 288 has, attached at its distal end, bias spring 294 which ispreferably coiled about core wire 284 and extends to fixed collar 292.Fixed collar 292 is preferably fixedly attached to the exterior surfaceof a distal portion of core wire 284.

Expandable member 290 is preferably formed, at a proximal portionthereof, of either discrete struts, or another suitable frame (such as aloose mesh) which allows blood and embolic material to flow therethrough. The proximal end 302 of expandable member 290 is coupled to adistal region of movable collar 288. The distal portion of expandablemember 290 is preferably formed of a filtering material which issuitable for allowing blood flow therethrough, but which will captureembolic, material being carried by the blood.

In one preferred embodiment, spring 294 is biased to force collars 288and 292 away from one another. Thus, as spring 294 urges collars 288 and292 away from one another, collar 288 retracts within transition tube286 pulling expandable member 290 into a collapsed position about corewire 284. However, in order to deploy collapsible member 290 as shown inFIG. 19, the operator preferably actuates a plunger (not shown) whichdelivers pressurized fluid through lumen 296. The pressurized fluidenters transition tube 286 and travels about the outer periphery ofinner core wire 284, thus forcing movable collar 288 to move distallyalong core wire 284. This overcomes the spring force exerted by spring294 thus causing collars 288 and 292 to move toward one another,relatively. This motion causes expandable member 290 to buckle andexpand outwardly to the deployed position shown in FIG. 19.

Expandable member 290 is collapsed by releasing the pressure appliedthrough lumen 296 (i.e., by causing the plunger to move proximally).This allows spring 294 to again urge collars 288 and 292 away from oneanother to collapse expandable member 290. In an, alternativeembodiment, the frame supporting expandable member 290 is imparted witha memory (such as a heat set, or a thermally responsive material whichassumes a memory upon reaching a transition temperature) such that theresting state of the frame supporting expandable member 290 is in acollapsed position. This eliminates the need for spring 294. Theexpandable member 290, in that preferred embodiment, is expanded usingthe hydraulic pressure provided by the pressurized fluid introducedthrough lumen 296, and it is collapsed by simply allowing the memory inexpandable member 290 to force fluid from transition tube 286 backthrough lumen 296.

FIGS. 20A and 20B illustrate another aspect in accordance with thepresent invention. A device 310 includes a mesh portion 312 supported bya frame 314. Expansion of frame 314 to the radially expanded positionshown in FIG. 20A is driven by an expandable member, such as a balloon,316 which is coupled to frame 314. Balloon 316 is coupled to a distalend of a distal hypotube 318, which is formed of a suitable material,such as nitinol. It should be noted that the distal tip of hypotube 318includes a spring tip 320.

Distal hypotube 318 is shown coupled to a proximal hypotube 322 whichhas a tapered portion 324 therein. In the preferred embodiment, proximalhypotube 322 is formed of a suitable material, such as stainless steel.A plunger 326 is longitudinally movable within the lumen of bothproximal hypotube 322 and distal hypotube 318.

Frame 314, and consequently mesh portion 312, are deployed by theoperator moving plunger 326 distally within the lumens of hypotubes 318and 322. This causes pressurized fluid to enter balloon 316, therebyinflating balloon 316 and driving deployment of frame 314 and mesh 312.In order to collapse frame 314 and mesh 312, the operator preferablymoves plunger 326 proximally within the lumens of tubes 318 and 322 towithdraw fluid from within balloon 316. Alternatively, mesh 312 or frame314 can have a memory set which is either in the inflated or collapsedposition such that the operator need only affirmatively move frame 314and mesh 312 to either the deployed or collapsed position, whichever isopposite of the memory set.

In either case it is desirable that the operator be able to lock plunger326 in a single longitudinal position relative to hypotubes 318 and 322.Thus, device 310 includes a locking region 328.

FIG. 20B illustrates locking region 328 in greater detail. FIG. 20Billustrates that, in locking region 328, plunger 326 has a plurality ofgrooves 330 formed in the outer radial surface thereof. Also, inaccordance with the present invention, FIG. 20B illustrates that one ofhypotubes 318 or 322 has an inwardly projecting portion 332. In onepreferred embodiment, inwardly projecting portion 332 includes aninwardly extending, deflectable, Annular rim which extends inwardly fromeither hypotube 318 or 322. In another preferred embodiment, theinwardly projecting portion 332 includes a plurality of discrete,fingers which extend inwardly from one of hypotubes 318 or 322 and whichare angularly displaced about the interior periphery of thecorresponding hypotube 318 or 322.

In operation, as the operator advances plunger 326 distally within thelumens of hypotubes 318 and 322, inwardly projecting portion 332 ridesalong the exterior periphery of plunger 326 until it encounters, one Ofgrooves 330. Then, inwardly projecting portion 332 snaps into the groove330 to lock plunger 326 longitudinally relative to tubes 318 and 322.

It should be noted that, in the preferred embodiment, both inwardlyprojecting portions 332 and grooves 330 are formed such that, whengentle pressure is exerted by the operator on plunger 326 relative tohypotubes 318 and 322, projection portions 332 follow the contour ofgrooves 330 up and out of grooves 330 so that plunger 326 can again befreely moved within the lumens of hypotubes 318 and 322. Thus, therelative interaction between projecting portions 332 and grooves. 330provides a ratcheting type of operation wherein plunger 326 can bereleasably locked into one of a plurality longitudinal positionsrelative hypotubes 318 and 322, since a plurality of grooves 330 areprovided. Plunger 326 can be moved back and forth longitudinally withinthe lumens of hypotubes 318 and 322 in a ratcheting manner and can belocked into one of a plurality of relative longitudinal positionsbecause there are a plurality of grooves 330 in the exterior of plunger326. It should also be noted, however, that in another preferredembodiment, a plurality of sets of inwardly projecting portions 332 areprovided along the inner longitudinal surface of hypotubes 318 and/or322. In that case, only a single groove 330 needs to be formed in theexterior surface of plunger 326; and the same type of ratcheting lockingoperation is obtained.

In the preferred embodiment, at least the exterior of hypotubes 318 and322, and preferably the exterior of plunger 326, are tapered. Thisallows device 310 to maintain increased flexibility. It should also benoted that, in the preferred embodiment, hypotubes 318 and 322 arepreferably sized as conventional guidewires.

FIG. 21A illustrates a protection device in accordance with anotherembodiment of the present invention. FIG. 21A illustrates distalprotection device 340. Device 340 is similar to devices 192 and 206shown in FIGS. 16A and 16B. However, in the preferred embodiment, device340 includes hoop-shaped frame 342, filter portion 344, and wire 346.Hoop-shaped frame 342 is preferably a self-expanding frame formed of awire which includes a shape memory alloy. In a more preferred embodimenthoop-shaped frame 342 is formed of a nitinol wire having a diameter in arange of approximately 0.002-0.004 inches.

Filter portion 344 is preferably formed of a polyurethane materialhaving holes therein such that blood flow can pass through filter 344,but emboli (of a desired size) cannot pass through filter 344 but areretained therein. In one preferred embodiment, filter material 344 isattached to hoop-shaped frame 342 with a suitable, commerciallyavailable adhesive. In another preferred embodiment, filter 344 has aproximal portion thereof folded over hoop-shaped frame 342, and thefilter material is attached itself either with adhesive, by stitching,or by another suitable connection mechanism, in order to secure it abouthoop-shaped frame 342. This connection is preferably formed by asuitable adhesive or other suitable connection mechanism.

Also, the distal end of filter 344 is preferably attached about theouter periphery of wire 346, proximate coil tip 348 on wire 346.

In one preferred configuration, filter 344 is approximately 15 mm inlongitudinal length, and has a diameter at its mouth (defined byhoop-shaped frame 342) of a conventional size (such as 4.0 mm, 4.5 mm, 5mm, 5.5 mm, or 6 mm). Of course, any other suitable size can be used aswell.

Also, in the preferred configuration, filter 344 is formed of apolyurethane material with the holes laser drilled therein. The holesare preferably approximately 100 μm in diameter. Of course, filter 344can also be a microporous membrane, a wire or polymer braid or mesh, orany other suitable, configuration.

Wire 346 is preferably a conventional stainless-steel guidewire havingconventional guidewire dimensions. For instance, in one embodiment, wire346 is a solid core wire having an outer diameter of approximately 0.014inches and an overall length of up to 300 cm. Also, in the preferredembodiment, wire 346 has a distal end 350, in a region proximate filter344, which tapers from an outer diameter at its proximal end which isthe same as the outer diameter of the remainder of wire 346, to an outerdiameter of approximately 0.055 inches at its distal end. At distalregion 350, guidewire 346 is preferably formed of stainless steel 304.

Of course, other suitable guidewire dimensions and configurations canalso be used. For example guidewires having an outer diameter ofapproximately 0.018 inches may also be used. For other coronaryapplications, different dimensions may also be used, such as outerdiameters of approximately 0.010 inches to 0.014 inches. Further, itwill be appreciated that the particular size of wire 346 will vary withapplication. Applications involving neural vasculature will require theuse of a smaller guidewire, while other applications will require theuse of a larger guidewire. Also, wire 346 can be replaced by a hollowguidewire, or hypotube of similar, or other suitable dimensions.

In addition, in order to make wire 342, hoop 346, or filter 344radiopaque, other materials can be, used. For example, radiopaque loadedpowder can be used to form a polyurethane sheath which is fitted overwire 346 or hoop 342, or which is implemented in filter 344. Also, hoop342 and wire 346 can be gold plated in order to increase radiopacity.Also, marker bands can be used on wire 346 or filter 344 to increase theradiopacity of the device.

In operation, hoop 342 (and thus filter 344) is preferably collapsed toa radially contracted position which more closely approximates the outerdiameter of wire 346. Methods of performing this contraction aredescribed later in the specification. Once retracted to a more lowprofile position, wire, 346 is manipulated to position hoop 342 andfilter 344 distal of a restriction to be treated. Then, the restrainingforce which is used to restrain hoop 342 in, the predeployment, lowprofile position is removed, and the superelastic properties of nitinolhoop 342 (or the shape memory properties of another, shape memory alloy)are utilized in allowing hoop 342 to assume its shape memory position.This causes hoop 342 to define a substantially lumen filling mouth tofilter 344 which is positioned distal of the restriction to be treated.

A suitable dilatation device is then advanced over wire 346 and is usedto treat the vascular restriction. Emboli which are carried by bloodflow distal of the restriction are captured by filter 344. After thedilatation procedure, filter 344, along with the emboli retainedtherein, are retrieved from the vasculature. Various retrievalprocedures and devices are described later in the specification.

By allowing hoop-shaped frame 342 to be unattached to wire 346, and onlyconnected to wire 346 through filter 344 (or other super structure usedto support filter 344), wire 346 is allowed to substantially floatwithin hoop 342 This configuration provides some advantages. Forinstance, hoop 342 can better follow the vasculature without kinking, orprolapsing (i.e., without collapsing upon itself). Thus, certainpositioning or repositioning of filter 344 can be accomplished with lessdifficulty.

FIG. 21B illustrates a protection device 352 in accordance with anotherembodiment of the present invention. Protection device 352 is similar toprotection device 340, and similar items are similarly numbered.However, rather than having simply a hoop-shaped frame 342 to supportfilter 344, and drive filter 344 into its expanded and deployedposition, device 352 includes frame 354 which includes a hoop-shapedportion, 356, and a pair of tails 358 and 360.

Tails 358 and 360 extend proximally from hoop-shaped port on 356 to anattachment region 362. In the preferred embodiment, tails 358 and 360are attached to wire 346 at attachment region 362 by soldering, welding,brazing, adhesive, or any other suitable attachment mechanism. In theembodiment shown in FIG. 21B, attachment sleeve 364, formed of aweldable material, is attached at its inner periphery to tails 358 and360. Sleeve 364 is then attached, using welding or brazing, to wire 346.

By providing tails 358 and 360, frame 354 is directly connected to wire346. However, tails 358 and 360 are provided so that the point ofattachment of frame 354 to wire 346 is located several millimetersproximal of hoop-shaped portion 356. This provides some additionalstructural integrity to frame 354, but still allows frame 354 tosubstantially float about wire 346 in the region of hoop-shaped frameportion 356.

FIG. 21C illustrates a protection device 366 in accordance with anotherembodiment of the present invention. Protection device 366 is similar toprotection devices 340 and 352 shown in FIGS. 21A and 21B, and similaritems are similarly numbered. However, device 366 includes hoop-shapedframe 368. Frame 368 is similar to frame 342 shown in FIG. 21A. However,unlike frame 342, hoop 368 does not allow wire 346 to float freelytherein. Instead, hoop 368 is directly attached to wire 346 atattachment point 370. This causes hoop-shaped frame 368 and filter 344to reside eccentrically about wire 346.

FIGS. 22A-22C illustrated one preferred embodiment ford delivering oneof devices 340, 352 and 366. For the sake of clarity, only device 352 isillustrated in FIGS. 22A-22C.

FIG. 22A illustrates delivery device 372. In the preferred embodiment,delivery device 372 includes proximal hub 374, shaft 376, and distalretaining section 378. Also, in one preferred embodiment, device 372also includes marker band 380. In the preferred embodiment, deliverydevice 372 is similar to a conventional balloon catheter in thatproximal hub 374 is a conventional hub, and shaft 376 is a conventionalballoon catheter shaft. Further, distal retaining section 378 ispreferably a conventional angioplasty balloon having an inflateddiameter of approximately 1.5-2.0 millimeters, but having its distal endcutoff such that the distal end 382 of balloon 378 is open.

Prior to insertion of device 372 into the vasculature, hoop-shaped frame354 is retracted into its low profile deployment position and iswithdrawn through end 382 into balloon 378. Then, the distal end ofballoon 378 is exposed to heat to heat shrink or heat set the distal endof balloon 378 around the radially retracted device 352. Device 372,including device 352, is then inserted in the vasculature either througha preplaced guide catheter, along with a guide catheter, or simplywithout a guide catheter utilizing coil tip. 348.

In any case, once device 372 is properly placed such that balloon 378 islocated distal of the restriction to be treated, distal protectiondevice 352 is then removed from within heat collapsed balloon 378. Inone preferred embodiment, the physician simply accomplishes longitudinalmovement of wire 346 relative to catheter 376. For instance, thephysician may simply hold wire 346 longitudinally in place and withdrawcatheter 376 proximally relative to wire 346 by pulling on hub 374. Thiscauses balloon 378 to move proximally relative to device 352, andthereby to expose device 352 to the vasculature.

FIG. 22B illustrates another preferred embodiment for removing device352 from within balloon 378. In the embodiment shown in FIG. 22B,syringe 384, which contains fluid, is inserted into coupling 386 in hub374. The physician then introduces pressurized fluid into the lumen ofcatheter 376. The pressurized fluid advances down the lumen of catheter376 to the distal end where it encounters collapsed balloon 378. Thepressure exerted on balloon 378 by the pressurized fluid causes balloon378 to open radially. Then, the physician withdraws catheter 376relative to device 352 thereby exposing device 352 to the vasculature.

In any case, once device 352 is no longer restrained by balloon 378,device 352 assumes its shape memory position in the vasculature, asillustrated in FIG. 22C. Thus, device 352 substantially forms alumen-filling basket or filter which allows blood to pass distallytherethrough, but which retains or captures embolic material carried bythe blood flow. The physician then simply removes device 372 from thevasculature, leaving device 352 in place during subsequent procedures.In one preferred embodiment, shaft 376 includes a predefined slit orscore from a region just proximal of marker band 380 to, or through, hub374. Thus, as the physician removes device 372, it can be peeled awayfrom device 352. Also, or alternatively, device 372 can be provided withan aperture in shaft 376 near its distal end. The proximal end of wire346 will thus lie, outside of shaft 376. Wire 346 can enter shaft 376through the aperture and extend through the distal end of shaft 376.This also facilitates easier withdrawal of device 372 over wire 346.

FIGS. 23A-23E illustrate Done preferred embodiment for retrieving one ofthe devices 340, 352 and 366 described in FIGS. 21A-21C. For the sake ofclarity, only device 352 is illustrated in FIGS. 23A-23E. FIG. 23Aillustrates retrieval device 388. Retrieval device 388 is preferablyformed of proximal shaft 390, mesh portion 392, and end cap 394. Items390, 392 and 394 preferably each have lumens therein to define apassageway for receiving wire 346. Also, wire 346 may optionally beprovided with an positive stop 396 (which can be embodied as aradiopaque marker band). Optional stop 396 may also simply be an annularring attached to wire 346 proximate to filter 344, or may be any othersuitable stop.

Proximal shaft 390 is preferably simply a polymer or nitinol tube sizedand configured to track over wire 346. End cap 394 is also preferablyformed to track over wire 346, but also contains radiopaque material toserve as a distal marker band for retrieval device 388. Mesh 392 ispreferably a braid or mesh formed of wire or polymer material havingsufficient flexibility that it can be deflected as described below,

Mesh 392 preferably has a proximal end coupled to proximal shaft 390, byadhesive, welding, or other suitable attachment mechanisms. Mesh 392also preferably includes a distal end connected to end cap 394, also bya suitable connection mechanism.

In order to retrieve filter 344, which likely contains embolic material,device 388 is inserted in the low profile position shown in FIG. 23A,over wire 346, to a position proximate filter 344. Then, device 388 isadvanced toward filter 344, until end cap 394 abuts positive stop 396,or the hoop-shaped frame 354. Continued advancement of proximal shaft390 relative to wire 346 causes compression of mesh 392. This results ina radial expansion of an intermediate portion of mesh 392 (between theproximal and distal ends of mesh 392). The radial expansion of meshportion 392 is illustrated in FIG. 23B.

By continuing to advance proximal shaft 390 relative to wire 346, theintermediate portion of mesh 392 is configured to bend over on itselfsuch that it is axially displaced toward filter 344, in the directiongenerally indicated by arrows 398 in FIG. 23C. In the preferredembodiment, mesh 392 is sized and configured such that, with continuedadvancement of proximal shaft 390 relative to wire 346, this actioncontinues as shown in FIGS. 23D and 23E until the intermediate portionof mesh 392 encompasses At least the mouth of filter 344. Also, in thepreferred embodiment, the intermediate portion of mesh 392, when drivenas described above, engages and contracts the mouth of filter 344 to alower profile position, such as that shown in FIG. 23E. In yet anotherpreferred embodiment, mesh 392 is sized and configured to substantiallyengulf the entire filter 344.

Once at least the mouth of filter 344 is encompassed by mesh 392 device388, along with device 352, are simply withdrawn from the vasculature.In one preferred embodiment in which a guide catheter is used, device388 and 352 are simply withdrawn either into the guide catheter and theguide catheter is removed with those devices, simultaneously, or devices388 and 352 are removed from the guide catheter prior to removal of theguide catheter. In another preferred embodiment, in which no guidecatheter is used, devices 388 and 352 are simply removed from thevasculature simultaneously.

It will also be appreciated, of course, that rather than providingdevice 388 with a single proximal tube 390 and end cap 394, a secondactuation tube or wire can also be provided which is attached to end cap394, and which extends back through the lumen in proximal tube 390 andis longitudinally movable relative to proximal shaft 390. In that way,the actuation wire or elongate member can be used to pull cap 394 closerto the distal portion of proximal shaft 390 in order to accomplish theaction illustrated in FIGS. 23A-23E. This feature is also illustrated inFIGS. 18A-18D which illustrate the mesh portion folded proximally ratherthan distally.

FIGS. 24A-24C illustrate another preferred embodiment in accordance withthe present invention, for retrieving any of the distal protectiondevices 340, 352 or 366 shown in FIGS. 21A-21C. For the sake of clarity,only device 352 is illustrated in FIGS. 24A-24C.

FIG. 24A illustrates retrieval device 400. Retrieval device 400preferably includes retrieval sheath 402, proximal locking device 404,dilator sheath 405, and nose cone 406. In the preferred embodiment,retrieval sheath 402 is preferably formed of polyether block amide(PEBAX) material having an outer diameter of approximately six French(i.e., approximately 2 mm) and having a shore D hardness ofapproximately 40. Also, retrieval sheath 402 preferably has a wallthickness of approximately 0.004 inches. Dilator sheath 405, and nosecone 406, are preferably formed of low density polyethylene, or highdensity polyethylene. Sheath 405 preferably has an outer diameter whichis approximately equal to the inner diameter of sheath 402. In addition,the inner diameter of sheath 405 and nose cone 406 is preferably justlarge enough to fit over, and track over, wire 346. Nose cone 406preferably has a proximal portion which is either attached to, or formedintegrally with, sheath 405. The outer diameter of the proximal portionof nose cone 406 is also approximately the same as the outer diameter ofsheath 405. However, nose cone 406 also preferably has a distal portionwhich tapers, or reduces along preferably a smooth curve, to an outerdiameter which terminates at the inner diameter of nose cone 406.

Proximal locking device 404 is preferably any suitable, and commerciallyavailable, locking device which can be configured to lock dilator sheath405 to guidewire 346.

In order to retrieve device 352 from the vasculature, device 400 ispreferably advanced over guidewire 346 to a position shown in FIG. 24B,in which the distal portion of nose cone 406 is Closely proximate, oradjacent to, either optional stop 396 or the mouth of filter 344. Then,proximal locking device 404 is actuated to lock dilator sheath 405 towire 346 so that wire 346 and dilator sheath 405 (as well as nose cone406) can be moved as a unitary piece.

Next, wire 346 (and hence dilator sheath 405 and nose cone 406) arewithdrawn longitudinally relative to retrieval sheath 402. This causesthe mouth of filter 344 to enter within the distal opening in retrievalsheath 402. This results in device 352 being positioned relative tosheath 402 as shown in FIG. 24C. Of course, wire 346 dilator sheath 405and nose cone. 406 can be withdrawn further into sheath 402 such thatthe entire filter 344, and wire tip 348, are disposed within the lumenof sheath 402.

In any case, once at least the mouth of filter 344 is within sheath 402,device 352 is configured to be removed from the vasculature. This can beaccomplished by either removing dilator sheath 405, nose cone 406 anddevice 352 as a unitary piece, leaving sheath 402 in place for laterremoval, or by removing sheath 402 with the remainder of the system,either through a guide catheter or simply through the vasculature,simultaneously. Also, where a guide catheter is used, device 352 anddevice 400 can be removed through the guide catheter leaving the guidecatheter in place, or the guide catheter can be removed simultaneouslywith the other devices 352 and 400.

It should be noted that all of the devices according to the presentinvention can optionally be coated with an antithrombotic material, suchas heparin (commercially available under the tradename Duraflow fromBaxter), to inhibit clotting.

Thus, in accordance with one preferred embodiment of the presentinvention, the superelastic properties of nitinol are used to form aframe at least in the area of the mouth of the distal protection filter.Thus, the distal protection device can be deployed, retrieved, andre-deployed any number of times without incurring plastic deformation.In addition, in other preferred embodiments in accordance with thepresent, invention, various deployment and retrieval techniques andsystems are provided which address various problems associated with suchsystems.

Although the present invention has been, described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without, departing from thespirit and scope of the invention.

1. An embolic protection device, comprising: an elongate wire memberhaving a proximal end and a distal end; a filter coupled proximal thedistal end of the elongate wire member, the filter having a wire loopadjacent the proximal end of the filter, the wire loop coupled to aproximally open mouth and a filter portion disposed distally of theproximally open mouth, the mouth having a center of cross-sectionalarea, the filter being eccentrically coupled on the elongate member suchthat the center of cross-sectional area is disposed to one side of theelongate wire member.
 2. The embolic protection device of claim 1wherein the loop is substantially radiopaque.